Help? PAL GC-disc read errors on PAL Wii

My PAL Wii started to make annoying noise when spinning discs. After reading that a noisy Wii's disc drive may scratch a disc, out of fear of it, my Wii hasn't been in use for few years a lot at all. In these years, I've tried the disc reader a few times, and maybe saw new scratches on the discs.

And the weird thing and my main point of posting this is, that some time later after it started to behave noisy, my Wii started to have disc read errors with PAL GC discs usually in few minutes or seconds after launching, but not with NTSC-J GC discs nor Wii discs of any region. At least of the ones I've used. All my PAL GC discs are about as scratchy as the NTSC-J ones, but one on them is scratchier. That one doesn't work (noticeably) better or worse than other PAL GC discs on my Wii.But on some periods of not using the disc drive for a few weeks, then starting to use it again, this happened sometimes: the disc read errors tended to occur later, maybe hour or two or few after launching, if at all. And then when its using has again become more frequent, also the disc read errors started to come in few minutes again.

All those discs work fine on another PAL Wii I've been using. No annoying noise and no disc read errors at all, but once with Brawl.

On both Wiis, I've used Gecko OS homebrew program to run NTSC-J discs.